1. Field of the Invention
The invention relates to a weighting apparatus for measuring the weight of a load of a load-carrier of a vehicle, which load-carrier is supported by at least one spring unit on a mobile structure, e.g. a wheeled chassis or bogie of the vehicle. The invention is described below particularly with application to hot metal carriers, known as hot metal mixers or torpedo cars used in iron and steel works, but is not limited to this application.
2. Description of the Prior Art
A weighing apparatus for vehicle loads is known from FR-A-2,436,975. This has means for measuring the elastic deformation of the spring unit of the vehicle under the weight of the load. The measuring includes a reference object which is coupled to the load carrier. Specifically a measuring plate is fitted as reference object to the cargo compartment of a vehicle in the form of a railway wagon. A pack of leaf springs of the railway wagon forms the spring unit. Reference pointers are mounted on the measuring plate as well as on the pack of leaf springs. The relative positions of the reference pointers is a measure of the load in the railway wagon.
This known system has a number of disadvantages, in particular when it is used during the loading of a hot metal mixer. A hot metal mixer is a railway vehicle which is used for example in a combined blast furnace and steelworks for conveying molten pig iron of about 1650.degree. C. from a blast furnace to a steel-making plant. The cargo compartment in a hot metal mixer is a mixer ladle, ellipsoid in shape. The mixer ladle is provided with trunnions by which it is located onto the wheeled substructures by means intervention of springs. The mixer ladle is provided with a filling hole.
To fill the hot metal mixer, it is positioned under the cast house of a blast furnace and an unscreened jet of pig iron from an iron runner coming out of the cast house items vertically through the filling hole into the hot metal mixer. As hot metal mixer is being filled, operators in the cast house monitor the pig iron from and there are no people in the immediate vicinity of the hot metal mixer. Consequently, with the known apparatus it is not possible to read off the weight of the charge of a hot metal mixer during loading, unless a worker is deployed specially to do so.
Another inconvenience of the known apparatus is that it is not provided with any electrical means for measuring and determining the weight of the charge.